1. Field of the Invention
This invention relates to a method for image regulation of color monitors in proof-viewing and an apparatus therefor. More particularly, the invention relates to such method and apparatus in which the image on a color monitor screen can be corrected so as to closely resemble the quality of color printings to be formed. Furthermore, in the present invention, the data of said color monitor regulation can be advantageously utilized to the correction or retouching in the practical color printing process, thus faithful and full-color reproduction of colored original can be easily obtained. The term "proof-viewing" used herein means the act of observing the proof image in order to correct the press plates in the plate-making.
2. Description of Prior Art
Pictures including photographs speak a universal language, attract attention, arouse interest, convey ideas, illustrate and clarify contents of text. This is especially true for colored pictures; accordingly, the demand for colored illustrations in printing is constantly increasing.
When multi-colored printings are made from a colored original according to the prior art, the color separation and retouching are carried out giving consideration to the printing conditions, and the proof plates must be made. Then, the proof sheet is made by printing on the substrate to be used by employing said proof plates and a proof press, and the printed proof sheet is observed to determine whether the retouching is properly effected and the original is well reproduced. As a matter of fact, it is seldom that a desired reproduction is made only by one proof-viewing, and therefore corrections and proof-viewing must be generally carried out several times in order to obtain satisfactory color printings.
For example, in case the proof sheet is rather reddish on the whole as compared with the colored original, the red plate has to be retouched again so as to reduce the red color content. Then, a new proof sheet is made to confirm that the red color is weakened, thus such corrections and proof printing must be repeated until a desired proof sheet can be obtained. Meanwhile, when a satisfactory reproduction is formed through the above trials, the press plates for practical use are made on the basis of the results obtained from the above corrections. However, the above-mentioned determination of printing conditions takes much labour and troubles in proof plate making and proof printing, and in addition, it takes a lot of time. Furthermore, the retouching of color plates requires special mechanical skill and artistic technique through knowledge of color composition.
To this proof-viewing method in the prior art, some electronic proof-viewing devices which utilizing television monitors have been worked out. As an example of such devices, Color Previewer was put on sale several years ago by Hazeltine Corporation in the U.S.A. In this device, each of four color continuous tone negatives is separately received by each independent optical system; several corrections are imparted to each color system, and an image is then reproduced on the color display screen of the device, whereby the proof-viewing can be carried out. Devices of this type are used for correcting the hues and tones of respective colors in conformity with the characteristics of paper and inks to be used on the basis of Neugebauer equations. The image, however, can not be fully approximated to the final printings and the operation of the device is somewhat difficult, so that it might hardly be put to practical use.